Earth’s Layers and Plate Tectonics
Unit Test Review
1) What creates the Earth’s magnetic field? Spinning of the Inner Core
2) What two things do geologists observe to help them understand Earth’s
interior?
Earthquakes & Seismic Waves
3) Describe a transform plate boundary.
When two plates slide past each other in the same or opposite direction.
Creates fault lines and earthquakes.
4) Order the Earth’s layers from the surface inward.
Crust, Mantle, Outer Core, Inner Core
5) Describe a divergent boundary.
When two plates move away, in opposite directions. Creates mid-ocean
ridges, new ocean floor, and rift valley.
6) What are two possible outcomes of continental crust converging with oceanic
crust? Trench or Subduction Zone
7) What type of boundary creates mountains?
Convergent Boundaries (Continental Crust-Continental Crust)
8) What is Pangaea? All the continents were together as a single landmass
9) What evidence was used to support the continental drift hypothesis?
Fossils of plants, animals, and humans/Same mountains found on different
continents
10) At what type of plate boundary would you find subduction occurring?
Convergent Boundary
11) Mid ocean ridges are created at divergent plate boundaries, when two
oceanic plates move away from each other. How come Earth isn’t growing
larger if some plates are moving a part? Other areas of Earth have
subduction occurring to the tectonic plates, where they are recycled back
into the Mantle
12) How is new crust created along the edges of tectonic plates?
Sea-floor spreading causes a mid-ocean ridge where new crust is formed.
Subduction happens when the oceanic plate goes under the continental plate
at a convergent boundary.
13) What causes crustal plates to move? Convection Currents
14) Where would you find the youngest rocks on the ocean floor? Mid-ocean
ridge
15) What happens to an oceanic plate that subducts under a continental plate?
Oceanic plate melts into magma in the Mantle, then becomes part of the
convection currents
16) Describe a convection current.
Heated magma in the Mantle rises, then cools off and sinks, because it
becomes more dense. This process repeats as the heat source, the Inner
Core, is available.
17) For the Extended response… you will be required to do the following:


Identify what causes the plates to move #13
Explain how the cause you identified causes the plates to move. #16
(Explain means give details, support your answer, describe)
Mantle, Inner Core, Density, Magma, Heat Source, Repeats

Describe how the Earth continues to make new crust but does not
increase in size. (you can use information from #11 and #15 of this sheet
to help you with this)